Objective To investigate the changes of lumbar bone histomorphometry after exposure to low frequency pulsed electromagnetic fields (PEMFs), and to further understand the effect of PEMFs on osteoporosis (OP) in ovariectomizedOP rats. Methods Sixty-six 3-month-old Sprague Dawley rats were randomly divided into 4 groups: group A(n=12), groupB (n=12), group C (n=12), and group D (n=30). In group A, the ovaries were not resected as sham-ovariectomy; in groupsB, C, and D, the ovaries were resected. At 12 weeks after ovariectomy, the rats were exposed to PEMFs at 8 Hz, 3.8 mT, and 40 minutes/ day for 30 days in group B; the rats were administered with premarin [0.065 mg/(kg·d) by gavage for 30 days] in group C; in group D, the rats were housed as ovariectomy control. The hair and activity of rats were observed; the levels of serum estradiol were determined. At 30 days after intervention, all rats were sacrificed to harvest the L4 vertebrae for bone histomorphometry. Results General observation showed hair loss and decreased activity in group D, and no abnormal appearances in groups A, B, and C. The level of serum estradiol in group A was significantly higher than that in group D [(54.93 ± 23.52) pg/mL vs. (31.99 ± 23.45) pg/mL] (t=2.345, P=0.029). Histological observation showed thinness of sclerotin, bigger medullary cavity, and sparse and thinner bone trabecula in group D; uniform bone trabecula with no breakage in groups A, B, and C at 30 days after intervention. The ratio of trabecular bone area in group B was significantly higher than that in group D (P lt; 0.05); it was higher than that in groups A and C, showing no significant difference (P gt; 0.05). The trabecular thickness in group B was significantly higher than that in group D (P lt; 0.05), but it was lower than that in groups A and C, showing no significant difference (P gt; 0.05). The trabecular number in group B was significantly lower than that in group D (P lt; 0.05), but it was higher than that in groups A and C, showing no significant difference (P gt; 0.05). The trabecular separation in group B was higher than that in group D and lower than that in groups A and C, showing no significant difference (P gt; 0.05). Conclusion PEMFs at 8 Hz and 3.8 mT can significantly improve the character of bone microstructure in ovariectomized OP rats, increase the ratio of bone trabecular area and trabecular thickness, and decrease the trabecular number.
Objective To study the effect of Shengguzaizaosan on experimental fracture healing. Methods Thirty six-month-old Chinchilla rabbits were made the models with 3 mm bone defect in the middle of two-side radius and were divided randomly into 3 groups: Shengguzaizaosan group(group A, n=10), Xianlinggubao group(groupB, n=10) and control group(group C, n=10). Five rabbits were sacrificed 14 days and31 days after operation respectively. The double marks with tetracyslin hydrochloride were given on the 4th day and the 5th day for the first mark and on the 11th day and the 12th day for the second mark in the rabbits sacrificed 14 days later,and on the 20th day and the 21st day for the first mark and on the 28th day andthe 29th day for the second mark in the rabbits sacrificed 31 days later. The samples were taken to make the bone histomorphometry study. Results When compared group A with group C, there were significant differences(P＜0.01) in osteoid area density, osteoid mean width, active osteoblastic surface, mineralization surface and dynamic parameters after 14 days,and in mean width of mineralization callus, active osteoblastic surface and mean depth of lacunae after31 days. There was a approximate effect between group B and group C. when compared group B with group A, there were significant differences(P＜0.05) in osteoclastic index,mineralization surface,bone formation rate after 14 days, and in osteoid surface,mean depth of lacunae and bone formation rate after 31 days. Conclusion Shengguzaizaosan can increase osteoid,accelerate mineralization rate and bone formation rate, and reduce mineralization lag time at early period of fracture. It can increase mineralization calluswidth and resorption of osteoclast at later period of fracture. To some extent, shengguzaizaosan can accelerate the experimental fracture healing.